
/*
Rec. 601
    SDTV, legacy video, JPEG
    Standard-definition TV, JPEG, older pipelines.
*/
float luminance601(float3 color)
{
    return 0.299 * color.r + 0.587 * color.g + 0.114 * color.b;
}


/*
Rec. 709
    HDTV, sRGB, modern rendering
    High-definition TV, sRGB, most modern engines and tone mapping
*/
float luminance709(float3 color)
{
    return 0.2126 * color.r + 0.7152 * color.g + 0.0722 * color.b;
}


/*
Rec. 2020
    UHDTV, wide gamut
    Ultra HD, wide color gamut workflows.
*/
float luminance2020(float3 color)
{
    return 0.2627 * color.r + 0.6780 * color.g + 0.0593 * color.b;
}

